U.S. patent application number 14/558131 was filed with the patent office on 2015-11-19 for power-over-ethernet (poe)-enabled network device and usb device power negotiation using usb to poe protocol conversion.
The applicant listed for this patent is Cisco Technology, Inc.. Invention is credited to Koussalya Balasubramanian, Rob Liston.
Application Number | 20150331464 14/558131 |
Document ID | / |
Family ID | 54538461 |
Filed Date | 2015-11-19 |
United States Patent
Application |
20150331464 |
Kind Code |
A1 |
Balasubramanian; Koussalya ;
et al. |
November 19, 2015 |
Power-over-Ethernet (POE)-Enabled Network Device and USB Device
Power Negotiation using USB to POE Protocol Conversion
Abstract
A Network-Universal Serial Bus (NUSB) adaptor exchanges
Power-over-Ethernet (PoE) packets with, and receives power from, a
Power Source Equipment (PSE) over a PoE connection with the PSE,
and exchanges Universal Serial Bus (USB) messages with, and
provides power to, a USB device over a USB connection with the USB
device. The NUSB adaptor converts between a USB power negotiation
protocol implemented between the USB device and the NUSB adaptor
and a PoE power negotiation protocol implemented between the NUSB
adapter and the network device.
Inventors: |
Balasubramanian; Koussalya;
(Santa Clara, CA) ; Liston; Rob; (Menlo Park,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cisco Technology, Inc. |
San Jose |
CA |
US |
|
|
Family ID: |
54538461 |
Appl. No.: |
14/558131 |
Filed: |
December 2, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61994205 |
May 16, 2014 |
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Current U.S.
Class: |
713/310 |
Current CPC
Class: |
G06F 1/26 20130101; G06F
13/4282 20130101; G06F 13/387 20130101; G06F 1/266 20130101; G06F
13/42 20130101; H04L 69/08 20130101; Y02D 30/00 20180101; G06F
2213/0042 20130101; H04L 12/10 20130101 |
International
Class: |
G06F 1/26 20060101
G06F001/26; H04L 12/10 20060101 H04L012/10; G06F 13/42 20060101
G06F013/42 |
Claims
1. A method comprising: at a Network-Universal Serial Bus (NUSB)
adaptor to exchange (i) Power-over-Ethernet (PoE) packets with, and
receive power from, a Power Source Equipment (PSE) over a PoE
connection with the PSE, and (ii) Universal Serial Bus (USB)
messages with, and provide power to, a USB device over a USB
connection with the USB device: receiving a USB power request from
the USB device that specifies a power-related parameter for use by
the USB device; converting the received USB power request to a PoE
power request that specifies the power-related parameter; sending
the PoE power request to the PSE; receiving a PoE response from the
PSE that indicates acceptance of the sent PoE power request;
converting the received PoE response to a USB response; and sending
the USB response to the USB device.
2. The method of claim 1, further comprising, at the NUSB adaptor:
receiving the specified power-related parameter from the PSE; and
providing the received specified power-related parameter to the USB
over the USB connection.
3. The method of claim 2, wherein the specified power-related
parameter is a power level or a voltage level.
4. The method of claim 1, wherein: the converting the received USB
power request includes converting the received USB power request to
one or more Link Layer Data Protocol (LLDP) power request packets;
and the sending the PoE power request includes sending the one or
more LLDP power request packets to the PSE using the LLDP.
5. The method of claim 4, wherein the USB power request includes
one or more USB messages including a USB message identifier (PID)
to indicate a power request and a type of power-related parameter,
an address of the USB device, and a value of the specified
power-related parameter.
6. The method of claim 4, wherein: the receiving a PoE response
includes receiving the PoE response as an LLDP response packet; and
the converting the received PSE response includes converting the
received LLDP response packet to the USB response.
7. The method of claim 1, further comprising, at the NUSB:
receiving a PoE power change request from the PSE; converting the
received PoE power change request to a USB power change request;
and sending the USB power change request from the NUSB to the USB
device.
8. The method of claim 7, further comprising, at the NUSB:
receiving a USB power change accept from the USB device; converting
the USB power change accept to a PoE power change accept; and
sending the PoE power change accept to the PSE.
9. The method of claim 8, further comprising, at the NUSB:
receiving a change in power level from the PSE; and forwarding the
changed power level to the USB device.
10. An apparatus comprising: a PoE interface to connect with a
Power Source Equipment over a PoE connection; a USB interface to
connect with a USB device over a USB connection; a controller
coupled to the PoE and USB interfaces, to: receive a USB power
request from the USB device that specifies a power-related
parameter for use by the USB device; convert the received USB power
request to a PoE power request that specifies the power-related
parameter; send the PoE power request to the PSE; receive a PoE
response from the PSE that indicates acceptance of the sent PoE
power request; convert the received PSE response to a USB response
that indicates the acceptance; and send the USB response to the USB
device.
11. The apparatus of claim 10, further comprising power circuitry,
to: receive the specified power-related parameter from the from the
PSE through the PoE interface; and provide the received specified
power-related parameter to the USB over the USB connection.
12. The apparatus of claim 11, wherein the specified power-related
parameter is a power level or a voltage level.
13. The apparatus of claim 10, wherein the controller: converts the
received USB power request by converting the received USB power
request to one or more Link Layer Data Protocol (LLDP) power
request packets; and sends the PoE power request by sending the one
or more LLDP power request packets to the PSE using the LLDP.
14. The apparatus of claim 13, wherein the USB power request
includes one or more USB messages including a USB message
identifier (PID) to indicate a power request and a type of
power-related parameter, an address of the USB device, and a value
of the specified power-related parameter.
15. The apparatus of claim 13, wherein the controller: receives a
PoE response by receiving the PoE response as an LLDP response
packet; and converts the received PSE response by converting the
received LLDP response packet to the USB response.
16. The apparatus of claim 10, wherein the controller further:
receives a PoE power change request from the PSE; converts the PoE
power change request to a USB power change request; and sends the
USB power change request from the NUSB adaptor to the USB
device.
17. The apparatus of claim 16, wherein the controller further:
receives a USB power change accept from the USB device; converts
the USB power change accept to a PoE power change accept; and sends
the PoE power change accept to the PSE.
18. The apparatus of claim 17, further comprising power circuitry
to: receive a change in power level from the PSE after the PoE
power change accept has been sent by the controller; and forward
the change in power level to the USB device.
19. A system comprising: a power source equipment (PSE); a
Universal Serial Bus (USB) device; and a Network-USB (NUSB) adaptor
to connect with the PSE over a PoE connection and with the USB
device over a USB connection, wherein: the NUSB adaptor and the USB
exchange USB messages with each other over the USB connection using
a USB power negotiation protocol; the NUSB adaptor and PSE exchange
PoE packets with each other over the PoE connection using a PoE
power negotiation protocol; the NUSB adaptor converts (i) messages
from the USB to the PoE power negotiation protocol to convey a
power request from the USB device to the PSE, and (ii) packets from
the PoE to the USB power negotiation protocol to convey a power
request acknowledgement from the PSE to the USB device; the PSE
provides power to the NUSB adaptor responsive to the power request;
and the NUSB adaptor forwards the power received from the PSE to
the USB device.
20. The system of claim 19, wherein: the USB device sends a USB
power request representative of the power request to the NUSB
adaptor using the USB power negotiation protocol; the NUSB adaptor
converts the USB power request to a PoE power request; and the NUSB
adaptor sends the PoE power request to the PSE using the PoE power
negotiation protocol.
21. The system of claim 20, wherein: the PSE sends power to the
NUSB adaptor responsive to the PoE power request; and the NUSB
adaptor includes power circuitry to receive the power from the PSE
and forward the power to the USB device.
22. The system of claim 20, wherein the PoE power negotiation
protocol is based on a Link Layer Data Protocol (LLDP) and the NUSB
adaptor converts the USB power request to an LLDP formatted power
request, and sends the LLDP formatted power request to the PSE
using the LLDP.
23. The system of claim 19, wherein: the NUSB adaptor further
converts (iii) packets from the PoE to the USB power negotiation
protocol to convey a power change request from the PSE device to
the USB device, and (iv) messages from the USB to the PoE power
negotiation protocol to convey a power change accept from the USB
device to the PSE; the PSE provides a change in power to the NUSB
adaptor responsive to the power change accept from the USB device;
and the NUSB adaptor forwards the changed power received from the
PSE to the USB device.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application No. 61/994,205 filed May 16, 2014, the entirety of
which is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to techniques to power
Universal Serial Bus (USB) devices through Universal Serial Bus
(USB) and Ethernet connections.
BACKGROUND
[0003] A Powered Device (PD) receives power from Power Source
Equipment (PSE), such as a Power-over-Ethernet (PoE)-enabled
network switch, over a Power-over-Ethernet (PoE) connection between
the PD and the PSE. The PSE and PD may use a PoE power negotiation
protocol to negotiate a power level that the PSE is to supply to
the PD. A Universal Serial Bus (USB) device receives power from an
external device over a USB connection between the USB device and
the external device. The USB device and the external device may use
a USB power negotiation protocol to establish a power level
supplied to the USB device. The PoE and USB power negotiation
protocols are incompatible with each other.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a diagram of an example communication system that
enables power negotiation between a Power-over-Ethernet
(PoE)-enabled network device and a Universal Serial Bus (USB)
device, according to an example embodiment.
[0005] FIG. 2 is an illustration of an example power negotiation
between the USB device and the network device through a
Network-NUSB (NUSB) adaptor that converts between USB and PoE power
negotiation protocols, according to an example embodiment.
[0006] FIG. 3 is an illustration of another example power
negotiation between the USB device and the network device through
the NUSB adaptor, according to an example embodiment.
[0007] FIG. 4 is a block diagram showing details of the network
device, the NUSB adaptor, and the USB device from FIG. 1, according
to an example embodiment.
[0008] FIG. 5 is a block diagram of an example generalized
controller that may be implemented in the network device, the NUSB
adaptor, and the USB device to perform respective operations to
implement techniques described herein, according to an example
embodiment.
[0009] FIG. 6 is an illustration of an example USB message format
for a USB power request, according to an example embodiment.
[0010] FIG. 7 is an illustration of an example USB message format
for a USB data message accompanying a USB power request, according
to an example embodiment.
[0011] FIG. 8 is an illustration of an example USB message format
for a USB power request response, a USB power change request, and a
USB power change response, according to an example embodiment.
[0012] FIG. 9 is an illustration of an example Link Layer Data
Protocol (LLDP) packet format for LLDP packets that may be
exchanged between the network device and the NUSB adaptor over a
PoE connection during power negotiations.
DESCRIPTION OF EXAMPLE EMBODIMENTS
Overview
[0013] Techniques presented herein relate to powering Universal
Serial Bus (USB) devices through USB and Ethernet connections. A
Network-USB (NUSB) adaptor (i) exchanges Power-over-Ethernet (PoE)
packets with, and receives power from, a Power Source Equipment
(PSE) over a PoE connection with the PSE, and (ii) exchanges
Universal Serial Bus (USB) messages with, and provides power to, a
USB device over a USB connection with the USB device. The NUSB
adaptor receives a USB power request from the USB device that
specifies a power-related parameter for use by the USB device and
converts the received USB power request to a PoE power request that
specifies the power-related parameter. The NUSB adaptor sends the
PoE power request to the PSE. The NUSB receives a PoE response from
the PSE that indicates acceptance of the sent PoE power request and
converts the received PoE response to a USB response. The NUSB
sends the USB response to the USB device.
Example Embodiments
[0014] Referring first to FIG. 1, there is shown a diagram of an
example communication system 100 that enables power negotiation
between a Power-over-Ethernet (PoE) enabled network device and a
Universal Serial Bus (USB) device. System 100 includes a PoE
network device 108, such as a network switch or router, accessible
through a communication network (not shown in FIG. 1), which may
include one or more wide area networks (WANs), such as the
Internet, and one or more local area networks (LANs). Network
device 108 includes multiple PoE enabled network ports (not
specifically shown in FIG. 1), one of which is connected to a
Network-USB (NUSB) adaptor device 112 over a PoE connection 114.
NUSB adaptor device 112 (referred to simply as NUSB adaptor 112) is
in turn connected to a USB endpoint or device 116 over USB
connection 118 (including standard USB cabling and connectors).
[0015] Network device 108 exchanges PoE (data) packets with NUSB
adaptor 112 and also operates as a Power Source Equipment (PSE) to
provide PoE power to the NUSB adaptor 112 over the PoE connection,
for example, in accordance with the IEEE 802.3 standard
extended/modified as described herein. NUSB adaptor 112 exchanges
low level USB (data) messages with USB device 116 over USB
connection 118, and also provides USB power to the USB device over
the USB connection. USB device 116 and USB connection 118 are
configured to operate in accordance with known and hereafter
developed USB standards such as, but not limited to, USB 1.0, 2.x,
and 3.x, and in accordance with modifications/extensions of the USB
standards presented herein.
[0016] According to techniques presented herein, USB device 116
negotiates for power with network device 108 (operating as a PSE)
through NUSB adaptor 112 and receives the negotiated power from the
network device through the NUSB adaptor. At a high-level, NUSB
adaptor 112 and USB device 116 perform power negotiation with each
other over USB connection 118 using a USB power negotiation
protocol that enables the USB device to request a required power
level. In turn, network device 108 and NUSB adaptor 112 perform
power negotiation with each other over PoE connection 114 using a
PoE power negotiation protocol to enable the NUSB adaptor to
request and then receive sufficient power from the network device
to satisfy the power request from the USB device. The PoE and USB
power negotiation protocols are not the same. Therefore, NUSB
adaptor 112 converts or bridges between the PoE and USB power
negotiation protocols. For example, NUSB adaptor 112 converts (i)
messages from the USB to the PoE power negotiation protocol to
convey power requests from USB device 116 to network device 108,
and (ii) packets from the PoE to the USB power negotiation protocol
to convey power request responses/acknowledgements from the network
device to the USB device. In other words, NUSB adaptor 112 converts
power negotiation-related USB messages to power negotiation-related
PoE packets and vice versa.
[0017] With reference to FIG. 2, there is an illustration of an
example power negotiation 200 between USB device 116 and network
device 108 that uses NUSB adaptor 112 to convert between the USB
and PoE power negotiation protocols. Power negotiation 200 is
initiated by USB device 116. In the example of FIG. 2, the PoE
power negotiation protocol is a Link Layer Data Protocol (LLDP)
that exchanges LLDP packets over PoE connection 114, although other
types of PoE power negotiation protocols may be used. LLDP
implements various protocol timers not shown in FIG. 2.
[0018] At 204, USB device 116 sends a USB power request formatted
as a USB message to NUSB adaptor 112 (and the NUSB adaptor receives
the request) over USB connection 118 using the USB power
negotiation protocol. The USB power request specifies a type of
power-related parameter, e.g., voltage, current, or power, and a
value of the power-related parameter, e.g., in Volts, Amps, or
Watts.
[0019] At 206, NUSB adaptor 112 converts the USB power request to a
PoE power request (e.g., an LLDP packet). The PoE power request
incorporates the specified type and value of the power-related
parameter from the USB power request.
[0020] At 208, NUSB adaptor 112 sends the PoE power request (e.g.,
the LLDP packet) to network device 108 over PoE connection 114
using the PoE power negotiation protocol (e.g., using LLDP).
[0021] At 212, network device 108 receives the PoE power request
and determines power availability in the network device. If network
device 108 has sufficient power available to satisfy the PoE power
request, flow proceeds to 216.
[0022] At 216, responsive to the PoE request received and the
determination made at 212, network device 108 sends a PoE power
response or acknowledgement (e.g., an LLDP packet) to NUSB adaptor
112 over PoE connection 114 using the PoE power negotiation
protocol (e.g., using LLDP), which is received at the NUSB adaptor.
The PoE power response may include a value of the power-related
parameter that matches the requested value in the PoE power request
and USB power request.
[0023] At 218, NUSB adaptor 112 converts the PoE power response to
a USB power response.
[0024] At 220, NUSB adaptor 112 sends the USB power response to USB
device 116 over USB connection 118 using the USB power negotiation
protocol.
[0025] At 222, network device 108 supplies the requested
power-related parameter (e.g., voltage, current, or power) to NUSB
adaptor 112 over PoE connection 114, which is received by the NUSB
adaptor.
[0026] At 224, NUSB adaptor 112 converts the received PoE power to
USB power suitable for USB device 116.
[0027] At 226, NUSB adaptor 112 provides the USB power to the USB
device 116. In another embodiment, the power convert operation 224
in NUSB adaptor 112 may be omitted, in which case the NUSB simply
passes the received PoE power directly to USB device 116 as is.
[0028] With reference to FIG. 3, there is an illustration of
another example power negotiation 300 between USB device 116 and
network device 108 that uses NUSB adaptor 112 to convert between
the USB and PoE power negotiation protocols. Power negotiation 300
is initiated by network device 108.
[0029] At 304, network device 108 sends a PoE power change
request/announcement (e.g., an LLDP packet) to NUSB adaptor 112
using the PoE power negotiation protocol (e.g., using LLDP). The
PoE change request indicates that network device 108 wants to
change its current power output to a different power output
specified in the PoE power change request.
[0030] At 306, NUSB adaptor 112 converts the PoE power change
request to a USB power change request.
[0031] At 308, NUSB adaptor 112 sends the USB power change request
to USB device 116 using the USB power negotiation protocol.
[0032] At 310, USB device 116 sends a USB power change accept to
NUSB adaptor 112 indicating that the USB device accepts the change
using the USB power negotiation protocol.
[0033] At 312, NUSB adaptor 112 converts the USB power change
accept to a PoE power change accept.
[0034] At 314, NUSB adaptor 112 sends the PoE power change accept
to network device 108 using the PoE power negotiation protocol.
[0035] At 316, responsive to the PoE power change accept, network
device 108 changes its PoE supply power and supplies the changed
PoE supply power to NUSB adaptor 112.
[0036] At 318, NUSB adaptor 112 converts the changed PoE supply
power to USB power.
[0037] At 320, NUSB adaptor 112 provides the USB power to USB
device 116.
[0038] With reference to FIG. 4, there is a block diagram showing
details of network device 108, NUSB adaptor 112, and USB device 116
in system 100, according to an embodiment. In the example of FIG.
4, the PoE power negotiation protocol uses LLDP; however, other PoE
power negotiation protocols may be used.
[0039] Network device 108 includes a PoE network port 402, an
Ethernet transmitter/receiver (transceiver) 404, an LLDP Packet
Processor or logic 405, a PSE controller 406, a System Power
Availability Checker and Allocator 408, and a power supply 410. PoE
network port 402 to mate with an Ethernet cable of PoE connection
114 and carry PoE packets "Data" to/from the cable and provide
"Power" to the PoE connection. Although only one network port is
depicted in FIG. 4, network device 108 may include multiple network
ports. Ethernet transmitter/receiver (transceiver) 404
transmits/receives PoE packets to/from network port 402.
[0040] LLDP Packet Processor or logic 405 interprets LLDP packets
received from Ethernet transceiver 404 (e.g., PoE power request)
and constructs LLDP packets (e.g., PoE power response and PoE power
change request) and sends the constructed LLDP packets to the
transceiver.
[0041] PSE controller 406 performs PSE operations, including, but
not limited to, PoE Powered Device (PD) detection, optional
classification, start-up, operation, and disconnect. PSE controller
406 includes power drive circuits that control a power draw by a PD
connected to network port 402 (e.g., NUSB adaptor 112). The power
drive circuits change drive circuit settings based on a control
signal 407 to correspondingly change a power, voltage, or current
level provided to the PD.
[0042] System Power Availability Checker and Allocator 408 checks
for/determine available un-utilized power in network device 108 and
allocates the available un-utilized power to satisfy PoE power
requests from NUSB adaptor 112. System Power Availability Checker
and Allocator 408 also generates control signal 407 to control PSE
controller 406.
[0043] Power supply 410 provides power for network device 108 and
PoE power for NUSB adaptor 112 (and indirectly for USB device
116).
[0044] NUSB adaptor 112 operates as a PD to sink power from network
device 108. NUSB adaptor 112 includes a PoE port 420, power
circuits 422, a USB connector 424, an LLDP Packet Processor or
logic 426, a USB Source Policy Engine or logic 428, an LLDP-to-USB
Protocol Converter 430, and a USB Finite State Machine (FSM)
432.
[0045] PoE port 420 mates with the cable of PoE connection 114.
Port 420 provides PoE power to NUSB circuits (described below) and
carries PoE packets ("Data") to/from PoE connection 114.
[0046] Power circuits 422 include: a PD circuit 424 to perform PD
operations including, for example, presenting to PSE controller 406
in network device 108 valid detection and classification signatures
responsive to the PSE operations (e.g., detection, classification,
and so on); and a power converter 426 (e.g., a Direct Current
(DC)-to-DC converter) to convert PoE power (e.g., PoE voltage) to
USB power (e.g., USB voltage) suitable for USB device 116. In an
example, the DC-DC converter converts PoE-standard prescribed
voltages to a standard 5 Volt USB voltage.
[0047] USB connector 424 mates with a USB cable of USB connection
118. Connector 424 provides USB power to the USB connection and
carries USB messages to/from the USB connection.
[0048] LLDP Packet Processor or logic 426 interprets LLDP packets
received from PoE connection 118 (e.g., PoE power response or PoE
power change request), constructs LLDP packets (e.g., PoE power
request and PoE power change accept), and sends the constructed
LLDP packets to the PoE connection.
[0049] USB Source Policy Engine or logic 428 receives and handles
(i) USB power requests and USB power change responses from USB
device 116, and (ii) USB power responses and USB change requests
destined for the USB device.
[0050] LLDP-to-USB Protocol Converter 430 converts between USB and
LLDP packets, e.g., from LLDP packets to corresponding USB messages
and vice versa.
[0051] USB Finite State Machine (FSM) 432, coupled between USB
connector 424 and USB Source Policy Engine 428, transmits/receives
bus-level USB transaction sequences over USB connection 118 so as
to comply with tight timing requirements imposed thereon and in
accordance with USB standards. USB FSM 432 generates bus-level USB
transaction sequences to be transmitted to USB device 116 based on
data from USB Source Policy Engine 428, and converts bus-level USB
transaction sequences from the USB device into data that can be
interpreted by the USB Source Policy Engine. Bus-level USB
transaction sequences include token, data, handshake, and special
messages exchanged over the USB connection, as is known. In
accordance with techniques described herein, the USB transaction
sequences are extended to also include the USB power request, USB
power request response, USB power change request, and USB power
change response messages mentioned above.
[0052] USB device 116 includes a USB connector 440 to mate with the
USB cable of USB connection 118. USB device 116 also includes a USB
Sink Policy Engine 442 to generate USB power requests based on
circuit load demand in the USB device, and sends control signals
444 to a USB Load Controller 446 whenever circuit load
power/voltage/current levels need to be changed. Engine 442 also
generates USB power request responses and USB power change
responses, and handles USB power change requests. USB Load
Controller 446 controls how much current is drawn by circuit loads
in USB device 116 at any given time.
[0053] With reference to FIG. 5, there is a block diagram of an
example generalized controller 500 that may be implemented in
network device 108, NUSB adaptor 112, and USB device 116 to perform
respective operations to implement techniques described herein.
There are numerous possible configurations for controller 500 and
FIG. 5 is meant to be an example. Controller 500 includes a
processor 544 and memory 548. The processor 544 is a
microcontroller or microprocessor, for example, configured to
execute software instructions stored in the memory 548.
[0054] The memory 548 may comprise read only memory (ROM), random
access memory (RAM), magnetic disk storage media devices, optical
storage media devices, flash memory devices, electrical, optical,
or other physical/tangible (e.g., non-transitory) memory storage
devices. Thus, in general, the memory 548 may comprise one or more
computer readable storage media (e.g., a memory device) encoded
with software comprising computer executable instructions and when
the software is executed (by the processor 544) it is operable to
perform the operations described herein. For example, the memory
548 stores or is encoded with instructions for Control logic 554 to
perform the operations/functions related to power negotiation
between USB device 116 and network device 108, using NUSB adaptor
112 as an intermediary. In addition, the memory 548 stores data 558
generated and used by processor 544 when executing logic 554.
[0055] When controller 500 is implemented in network device 108,
logic 554 may include LLDP Packet Processor or logic 405 and System
Power Availability Checker and Allocator 408.
[0056] When controller 500 is implemented in NUSB adaptor 112,
logic 554 may include LLDP Packet Processor or logic 426, USB
Source Policy Engine 428, and LLDP-to-USB Protocol Converter
430.
[0057] When controller 500 is implemented in USB device 112, logic
554 may include USB Sink Policy Engine 442.
[0058] With reference to FIG. 6, there is an illustration of an
example USB message format 600 for a USB power request. The USB
message format 600 includes a packet/message identifier (PID) field
that is set to "A" to indicate the message is a USB power request,
where A represents a PID value not currently in use for standard
token, handshake, data, and special USB messages. USB message
format 600 also includes SYNC, ADDR (address), ENDP (endpoint), CRC
(cyclic redundancy check), and EOP (end of packet) fields.
[0059] With reference to FIG. 7, there is an illustration of an
example USB message format 700 for a USB data message accompanying
a USB power request. USB message format 700 includes a packet
identifier (PID) field that may be set to (i) "B" to indicate the
Data to follow is a power-related parameter type, e.g., V=Voltage,
I=Current, or P=Power, or (ii) "C" to indicate the Data to follow
is a power-related parameter value, e.g., Volts, Amps (A), or Watts
(W), where B and C represent PID values not currently in use.
[0060] With reference to FIG. 8, there is an illustration of an
example USB message format 800 for a USB power request response
(PID="D"), a USB power change request (PID="E"), or a USB power
change response (PID="F"), where D, E, and F represent PID values
not currently in use.
[0061] With reference to FIG. 9, there is an illustration of an
example LLDP packet format 900 for LLDP packets that may be
exchanged over PoE connection 114 in power negotiations 200 and
300. LLDP packet format 900 includes a set of fields 904 defined in
accordance with the existing IEEE 802.3 standard and new fields 906
that modify or extend the standard in accordance with the
techniques presented herein. A new field 910 specifies a packet
type, e.g., PoE power request, PoE power response, PoE power change
request, or PoE power change accept. A new field 912 specifies a
type of power-related parameter, e.g., V (volts), I (current), or P
(power). A new field 914 specifies a value of the specified power
related parameter type, e.g., Volts, Amps, or Watts.
[0062] In summary, in one form, a method is provided comprising: at
a Network-Universal Serial Bus (NUSB) adaptor to (i) exchange
Power-over-Ethernet (PoE) packets with, and receive power from, a
Power Source Equipment (PSE) over a PoE connection with the PSE,
and (ii) exchange Universal Serial Bus (USB) messages with, and
provide power to, a USB device over a USB connection with the USB
device: receiving a USB power request from the USB device that
specifies a power-related parameter for use by the USB device;
converting the received USB power request to a PoE power request
that specifies the power-related parameter; sending the PoE power
request to the PSE; receiving a PoE response from the PSE that
indicates acceptance of the sent PoE power request; converting the
received PoE response to a USB response; and sending the USB
response to the USB device.
[0063] In another form, an apparatus is provided comprising: a PoE
interface to connect with a Power Source Equipment over a PoE
connection; a USB interface to connect with a USB device over a USB
connection; a controller coupled to the PoE and USB interfaces, to:
receive a USB power request from the USB device that specifies a
power-related parameter for use by the USB device; convert the
received USB power request to a PoE power request that specifies
the power-related parameter; send the PoE power request to the PSE;
receive a PoE response from the PSE that indicates acceptance of
the sent PoE power request; convert the received PSE response to a
USB response that indicates the acceptance; and send the USB
response to the USB device.
[0064] In yet another form, a system is provided comprising: a
power source equipment (PSE); a Universal Serial Bus (USB) device;
and a Network-USB (NUSB) adaptor to connect with the PSE over a PoE
connection and with the USB device over a USB connection, wherein:
the NUSB adaptor and the USB exchange USB messages with each other
over the USB connection using a USB power negotiation protocol; the
NUSB adaptor and PSE exchange PoE packets with each other over the
PoE connection using a PoE power negotiation protocol; the NUSB
adaptor converts (i) messages from the USB to the PoE power
negotiation protocol to convey a power request from the USB device
to the PSE, and (ii) packets from the PoE to the USB power
negotiation protocol to convey a power request acknowledgement from
the PSE to the USB device; the PSE provides power to the NUSB
adaptor responsive to the power request; and the NUSB adaptor
forwards the power received from the PSE to the USB device.
[0065] Although the techniques are illustrated and described herein
as embodied in one or more specific examples, it is nevertheless
not intended to be limited to the details shown, since various
modifications and structural changes may be made within the scope
and range of equivalents of the claims.
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